CrossFireX in the Notebook

CrossFireX in the Notebook

The new A-series APUs are designed to enhance integrated graphics performance as well as media related acceleration. As such, a lot of the processor's transistor budget went into building the GPU. According to AMD, as much as 50% of the die space have been allocated to the GPU, leaving the rest for the CPU and other subsystems. But this doesn't mean that its CPU is crippled since their latest 32nm process technology does give them the opportunity to integrate more transistors. However, if you compared the CPU subsystem with its current Phenom range of processors, you'll find that it's missing the large L3 cache which is part of Phenom's balanced cache architecture that helps shorten access time to highly accessed data. Instead, AMD increased the L2 cache size of its individual cores to 1MB each. This may help improve the performance of its individual cores, but it probably would not be comparable to their desktop CPUs. One must understand that the APUs are designed for graphics and media and it may not necessarily excel in general purpose computing workloads.

However, when it comes to graphics, the A-series APU does look promising from the start. With a Radeon class GPU built into the same CPU die, one can expect very decent graphics performance right off the APU. This presents users with a very affordable gaming notebook, an area that Intel is currently gaining much traction with their 2nd generation Core processors. Intel's effort to capture the integrated graphics market with Sandy Bridge may change when OEMs start shipping notebook models equipped with AMD's latest A-series APUs.

For notebooks that need the extra bump in graphics performance, AMD's latest A-series APUs will offer manufacturers the option to implement AMD's CrossFireX technology in the notebook. The APU's GPU is built with the ability to pair with another Radeon discrete GPU in a CrossFireX configuration to give greater speed improvements to gaming. Obviously, you'll find most implementations using an asymmetrical setup but CrossFireX will work nonetheless.

The ability to configure multi-GPU graphics is the real deal for AMD's latest A-series APUs. The flexibility to pair any discrete Radeon GPU with the APU is one of the most attractive feature we've come across so far. You can say that AMD has one-up Intel this time around and it would be hard for Intel to catch up unless they have discrete graphics solutions like AMD. Even NVIDIA is being sidelined for good since all AMD Fusion gaming-class notebooks would be using an AMD Radeon discrete GPU over NVIDIA's GeForce - simply because of the added performance from CrossFireX. So if you ever come across an AMD Fusion notebook with an NVIDIA GeForce discrete graphics, you may want to reconsider (unless of course the discrete GeForce is way more powerful and cheaper than the AMD CrossFireX option).

Below, you'll see an example of the various configurations using the A-series APU and the discrete Radeon component:-

AMD Radeon Dual Graphics Configurations & Branding Model Number

Discrete Radeon HD
Graphics Unit

AMD A8 series (Radeon 6620G) + Discrete

AMD A6 series (Radeon 6520G) + Discrete

6770M

6775G2

6775G2

6750M

6755G2

6755G2

6730M

6760G2

6740G2

6650M

6740G2

6720G2

6630M

6690G2

6680G2

6490M

6645G2

6545G2

6470M

6640G2

6540G2

6450M

6640G2

6540G2

As you can see in the table above, pairing the APU with a relatively powerful discrete part does not necessarily yield a lot more performance, as far as the branding model number goes.